1. Field of the Invention
The present invention relates to a positional sensor, and more particularly to a capacitance type of non-contact sensor for detecting the position of an object to be detected, such as dielectric material.
2. Description of the Background Art
Japanese patent laid-open publication No. 332312/1998 discloses such a type of non-contact sensor in which settings for efficiently utilizing a desired detectable range, such as a distance from the sensor to an object to be detected, are readily effected and also an offset or the like is easily adjustable. The non-contact sensor disclosed comprises a limit detector for detecting that an output value from the sensor indicates the limit position of the linear detectable range, and a display unit for indicating that the limit detector has detected that it is positioned at the limit position stated above. With this configuration, the sensor is adjustable to render the sensor output value to be zero.
Although the above conventional method of sensor adjustment makes it easier to adjust the offset at the limit position of the detectable range, the optimization of the offsets throughout the entire detectable range is not taken into account. Consequently, the gain and offset could not optimally be adjusted.